Mountain bikers are constantly exploring the world around them, looking for new trails to discover. But as our world shrinks, unridden trail networks are harder and harder to find. In "Forgotten Dirt", professional mountain biker Matt Hunter and a small team of riders travel to the remote Wakhan Corridor in Afghanistan on a world first mountain bike expedition. Ironically, the search for new trails leads to some of the oldest trails on earth. Watch the full story unfold, August 6th, 2013.